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AFM / ΑΦΜ Validator (Greece Tax ID)

Validate authenticity, structural format, and checksum of Greek AFM / ΑΦΜ numbers.

About Greek AFM Validation

This tool checks whether the AFM has exactly 9 digits and verifies that the check digit strictly matches the Module 11 algorithm defined by the Greek tax authority AADE.

Supports inputs with or without 'EL'/'GR' prefixes and performs real-time client-side validation with complete privacy.

AFM Validation Algorithm

  1. Remove any formatting and 'EL'/'GR' prefixes, ensuring exactly 9 numeric digits remain.
  2. Calculate the weighted sum of the first 8 digits multiplied by powers of 2 (256 down to 2).
  3. Compute the expected check digit as (Sum % 11) % 10.
  4. Compare expected check digit with the 9th digit. If equal, the AFM is valid.

Frequently Asked Questions & Technical Guidelines